Online Resources:
General:
Celtic Polytheism on Wikipedia - Wikipedia's portal for Celtic polytheism
CR FAQ - Celtic Reconstructionism Frequently Asked Questions, a nice go-to resource
Celtic Texts on the Sacred Texts Archive - Lots of books and documents well worth a read
CeltNet Celtic Pages - I'm pretty sure this site has literally every Celtic deity in its index
Earth, Sea, and Sky - An e-publication for Celtic Reconstructionism
e-Keltoi: Journal of Interdisciplinary Celtic Studies - what is says; plenty of articles on Iron Age culture and archaeology, with an entire volume devoted to the Celiberians!
Imbas - General CR resources
Kelticos - reenactment-centric forum for the Celtic Iron Age, lots of info
Mary Jones - Home of the Celtic Encyclopedia and the Celtic Literature Collective
Proto-Indo-European Religion - not Celtic, but a good reference for PIE religion and deities for comparison
Gaelic Resources:
Gaol Naofa - Gaelic polytheism resources
Ireland Abroad - myths and topics in indexed form
Irish Mythology on MyGuide Ireland - neat page on the survival of Irish mythology in modern times
Mythical Ireland - Irish mythology, sacred sites, and archaeology
The Myths of the Gods: Structures in Irish Mythology by Alan Ward - a nice long analysis on of deity types and classifications in Irish mythology, with cross-Celtic and Indo-European comparisons
Tairis - Gaelic polytheism resources
Voices from the Dawn - ancient monuments in Ireland and their folklore
Gaulish Resources:
Acy-Romance - Detailed interactive site on the territory of the Gaulish Remi, their sacred sites, history
À la recherche des fêtes celto-romaines - a short but very useful essay collecting dates of Gaulish deity insciptions across Central Europe
Calendrier Gaulois Astronomique Restitué : Siècle gaulois de -0151 à -0122 - digital version of the Coligny Calendar taking into account the time span between 151 and 122 BCE
Cernunnos: Origin and Transformation of a Celtic Divinity by Phyllis Fray Bober, American Journal of Archaeology - an article on Cernunnos on JSTOR
Condēuios - a Gaulish reconstructionist polytheist’s scribd page full of essays and data on the gods and Gaulish religion; lots of articles in both English and Portuguese
David Ficker-Wilbar - Cernunnos: Looking Another Way - a useful resource on Cernunnos
Deo Mercurio - a very excellent Gallo-Roman resource focusing on the religion of the Treverii
Epona.net - website devoted to Epona, the Gaulish goddess of horses, and perhaps a few other things as well
Télécharger Coligny - Coligny Calendar app with moon phases included
Gaulish Polytheism Facebook Community - Community for Gaulish polytheists on facebook, full of several good resources
L'Arbre Celtique - Great resource if you can read French, though not particularly aimed at religion
Maruadiat es Gaul - an online group on the site Ancient Worlds devoted to discussion of Gaulish history and archaeology
Welsh/Brythonic Resources:
Dun Brython - Brythonic polytheism site, aimed at Iron Age religion rather than medieval; many shared concepts and deities with Gaul
The Mabinogion - a website devoted to the Welsh Mabinogion and its history
Celtic Polytheism on Wikipedia - Wikipedia's portal for Celtic polytheism
CR FAQ - Celtic Reconstructionism Frequently Asked Questions, a nice go-to resource
Celtic Texts on the Sacred Texts Archive - Lots of books and documents well worth a read
CeltNet Celtic Pages - I'm pretty sure this site has literally every Celtic deity in its index
Earth, Sea, and Sky - An e-publication for Celtic Reconstructionism
e-Keltoi: Journal of Interdisciplinary Celtic Studies - what is says; plenty of articles on Iron Age culture and archaeology, with an entire volume devoted to the Celiberians!
Imbas - General CR resources
Kelticos - reenactment-centric forum for the Celtic Iron Age, lots of info
Mary Jones - Home of the Celtic Encyclopedia and the Celtic Literature Collective
Proto-Indo-European Religion - not Celtic, but a good reference for PIE religion and deities for comparison
Gaelic Resources:
Gaol Naofa - Gaelic polytheism resources
Ireland Abroad - myths and topics in indexed form
Irish Mythology on MyGuide Ireland - neat page on the survival of Irish mythology in modern times
Mythical Ireland - Irish mythology, sacred sites, and archaeology
The Myths of the Gods: Structures in Irish Mythology by Alan Ward - a nice long analysis on of deity types and classifications in Irish mythology, with cross-Celtic and Indo-European comparisons
Tairis - Gaelic polytheism resources
Voices from the Dawn - ancient monuments in Ireland and their folklore
Gaulish Resources:
Acy-Romance - Detailed interactive site on the territory of the Gaulish Remi, their sacred sites, history
À la recherche des fêtes celto-romaines - a short but very useful essay collecting dates of Gaulish deity insciptions across Central Europe
Calendrier Gaulois Astronomique Restitué : Siècle gaulois de -0151 à -0122 - digital version of the Coligny Calendar taking into account the time span between 151 and 122 BCE
Cernunnos: Origin and Transformation of a Celtic Divinity by Phyllis Fray Bober, American Journal of Archaeology - an article on Cernunnos on JSTOR
Condēuios - a Gaulish reconstructionist polytheist’s scribd page full of essays and data on the gods and Gaulish religion; lots of articles in both English and Portuguese
David Ficker-Wilbar - Cernunnos: Looking Another Way - a useful resource on Cernunnos
Deo Mercurio - a very excellent Gallo-Roman resource focusing on the religion of the Treverii
Epona.net - website devoted to Epona, the Gaulish goddess of horses, and perhaps a few other things as well
Télécharger Coligny - Coligny Calendar app with moon phases included
Gaulish Polytheism Facebook Community - Community for Gaulish polytheists on facebook, full of several good resources
L'Arbre Celtique - Great resource if you can read French, though not particularly aimed at religion
Maruadiat es Gaul - an online group on the site Ancient Worlds devoted to discussion of Gaulish history and archaeology
Welsh/Brythonic Resources:
Dun Brython - Brythonic polytheism site, aimed at Iron Age religion rather than medieval; many shared concepts and deities with Gaul
The Mabinogion - a website devoted to the Welsh Mabinogion and its history
Offline Resources:
General Celtic:
The Ancient Celts by Barry Cunliffe
Celtic Britain by Charles Thomas
Celtic Ornament in the British Isles by E.T. Leeds
Celtic Warrior: 300 BC – AD 100 by Stephen Allen and Wayne Reynolds
The Celtic World edited by Miranda J. Green
The Celts edited by Venceslas Kruta et. al.
Coinage in the Celtic World by Daphne Nash
Dictionnaire de la langue gauloise by Xavier Delamarre
The Forts of Celtic Britain by Angus Konstam and Peter Bull
The Gallic War by Julius Caesar
The Life and Death of a Druid Prince by Anne Ross and Don Robins
The Philosopher and the Druids by Philip Freeman
Rome’s Enemies (2): Gallic & British Celts by Peter Wilcox and Angus McBride
Rome’s Enemies (4): Spanish Armies by Rafael Martinez and Angus McBride
War, Women, and Druids: Eyewitness Reports and Early Accounts of the Ancient Celts by Philip Freeman
The World of the Celts by Simon James
The World of the Druids by Miranda J. Green
Celtic Myths and Folklore:
Albion: A Guide to Legendary Britain by Jennifer Westwood
Celtic Fairy Tales by Joseph Jacobs
The High Kings by Joy Chant and George Sharp
The Mabinogion translated by Lady Charlotte Guest
The Tain translated by Thomas Kinsella
Celtic Religion:
Cauldron of the Gods: A Manual of Celtic Magick by Jan Fries
Celtic Curses by Bernard Mees
The Celtic Gauls: Gods, Rites and Sanctuaries by Jean Louis Bruneaux
Celtic Myths by Miranda J. Green
Dictionary of Celtic Myth and Legend by Miranda J. Green
The Druids by Stuart Piggot
The Gods of Roman Britain by Miranda J. Green
Les dieux de la Gaule by Paul-Marie Duval
Monnaies gauloises et mythes celtiques by Paul-Marie Duval
Pagan Celtic Britain by Anne Ross
Symbol & Image in Celtic Religious Art by Miranda J. Green
Indo-European Religion and Comparative Religion:
Death, War, and Sacrifice: Studies in Ideology and Practice by Bruce Lincoln
Deep Ancestors by Ceisiwr Serith
The Indo-European "Smith" (Journal of Indo-European Studies Monograph Series 58) by Václav Blažek
Lady With a Mead Cup by Richard J. Enwright
Myths and Symbols in Pagan Europe by H.R. Ellis Davidson
Roman Religion: A Sourcebook by Valerie M. Warrior
General Pagan:
A Book of Pagan Prayer by Ceisiwr Serith
Fields of Stone: New Roots from Rocky Soil by Hearthstone
Hoofprints in the Wildwood edited by Richard Derks
A Pagan Ritual Prayer Book by Ceisiwr Serith
Divination:
Alchemy and the Tarot by Robert M. Place
Secret Games of the Gods: Ancient Ritual Systems in Board Games by Nigel Pennick
Random Nonfiction:
The Bridge to Humanity: How Affect Hunger Trumps the Selfish Gene by Walter Goldschmidt
Discovering Old Board Games by R.C. Bell
Europe Between the Oceans by Barry Cunliffe
Olympia: Cult, Sport, and Ancient Festival by Ulrich Sinn
Scythian and Thracian antiquities by Michael Vickers
The Vikings and Their Origins by David M. Wilson
Viking Weapons and Combat Techniques by William R. Short
Fiction and Literature:
The Bone Forest by Robert Holdstock
The Hollowing by Robert Holdstock
Lavondyss by Robert Holdstock
Merlin's Wood by Robert Holdstock
Mythago Wood by Robert Holdstock
The Paradise War by Stephen Lawhead
The Silver Hand by Stephen Lawhead
The Ancient Celts by Barry Cunliffe
Celtic Britain by Charles Thomas
Celtic Ornament in the British Isles by E.T. Leeds
Celtic Warrior: 300 BC – AD 100 by Stephen Allen and Wayne Reynolds
The Celtic World edited by Miranda J. Green
The Celts edited by Venceslas Kruta et. al.
Coinage in the Celtic World by Daphne Nash
Dictionnaire de la langue gauloise by Xavier Delamarre
The Forts of Celtic Britain by Angus Konstam and Peter Bull
The Gallic War by Julius Caesar
The Life and Death of a Druid Prince by Anne Ross and Don Robins
The Philosopher and the Druids by Philip Freeman
Rome’s Enemies (2): Gallic & British Celts by Peter Wilcox and Angus McBride
Rome’s Enemies (4): Spanish Armies by Rafael Martinez and Angus McBride
War, Women, and Druids: Eyewitness Reports and Early Accounts of the Ancient Celts by Philip Freeman
The World of the Celts by Simon James
The World of the Druids by Miranda J. Green
Celtic Myths and Folklore:
Albion: A Guide to Legendary Britain by Jennifer Westwood
Celtic Fairy Tales by Joseph Jacobs
The High Kings by Joy Chant and George Sharp
The Mabinogion translated by Lady Charlotte Guest
The Tain translated by Thomas Kinsella
Celtic Religion:
Cauldron of the Gods: A Manual of Celtic Magick by Jan Fries
Celtic Curses by Bernard Mees
The Celtic Gauls: Gods, Rites and Sanctuaries by Jean Louis Bruneaux
Celtic Myths by Miranda J. Green
Dictionary of Celtic Myth and Legend by Miranda J. Green
The Druids by Stuart Piggot
The Gods of Roman Britain by Miranda J. Green
Les dieux de la Gaule by Paul-Marie Duval
Monnaies gauloises et mythes celtiques by Paul-Marie Duval
Pagan Celtic Britain by Anne Ross
Symbol & Image in Celtic Religious Art by Miranda J. Green
Indo-European Religion and Comparative Religion:
Death, War, and Sacrifice: Studies in Ideology and Practice by Bruce Lincoln
Deep Ancestors by Ceisiwr Serith
The Indo-European "Smith" (Journal of Indo-European Studies Monograph Series 58) by Václav Blažek
Lady With a Mead Cup by Richard J. Enwright
Myths and Symbols in Pagan Europe by H.R. Ellis Davidson
Roman Religion: A Sourcebook by Valerie M. Warrior
General Pagan:
A Book of Pagan Prayer by Ceisiwr Serith
Fields of Stone: New Roots from Rocky Soil by Hearthstone
Hoofprints in the Wildwood edited by Richard Derks
A Pagan Ritual Prayer Book by Ceisiwr Serith
Divination:
Alchemy and the Tarot by Robert M. Place
Secret Games of the Gods: Ancient Ritual Systems in Board Games by Nigel Pennick
Random Nonfiction:
The Bridge to Humanity: How Affect Hunger Trumps the Selfish Gene by Walter Goldschmidt
Discovering Old Board Games by R.C. Bell
Europe Between the Oceans by Barry Cunliffe
Olympia: Cult, Sport, and Ancient Festival by Ulrich Sinn
Scythian and Thracian antiquities by Michael Vickers
The Vikings and Their Origins by David M. Wilson
Viking Weapons and Combat Techniques by William R. Short
Fiction and Literature:
The Bone Forest by Robert Holdstock
The Hollowing by Robert Holdstock
Lavondyss by Robert Holdstock
Merlin's Wood by Robert Holdstock
Mythago Wood by Robert Holdstock
The Paradise War by Stephen Lawhead
The Silver Hand by Stephen Lawhead